While your basic premise of systemic undercounting of Black and Latino workers is correct, that changed during the 1980s (source: https://www.bls.gov/mlr/1999/12/art1full.pdf). Housework by (predominantly) women has never been counted. And the share of white male workers has declined since the 1950s. As the linked article states, “In contrast to the labor force participation of women, those of men decreased significantly during the 1950–98 period” (largely because of better disability insurance; disabled/seriously injured men had no choice but to work 50+ years ago) .And, again, the population has more than doubled since 1954. Even if the BLS were consistently undercounting people of color, we’d definitely notice if roughly a third of the population were still undercounted in labor force participation.

In any case, changes in how the data were collected/interpreted 40 or 70 years ago still don’t account for the fact that we have roughly 22M more workers today than twenty years ago.

Edit: Updated with partial reason for decline among white male workers

This is ahistorical nonsense. The lowest labor force participation on record (since we started tracking) was 58.1% in December 1954 (source: https://fred.stlouisfed.org/series/CIVPART). Remember, far fewer women worked then. The US population in 1954 was roughly 154M people. Today it is roughly 336M (source: https://www.census.gov/data/tables/time-series/dec/popchange-data-text.html). For added context, unemployment during the Great Depending was somewhere around 25% (source: https://www.bls.gov/opub/mlr/1948/article/pdf/labor-force-employment-and-unemployment-1929-39-estimating-methods.pdf) and much higher among people of color and women. So, yes, there are far more workers today and far lower unemployment.

Labor force participation rate has declined from its all-time high in the late 90s, but population has increased at the same time. In 2003, when the labor force participation rate was above 65%, there were roughly 138M workers in the US. In January 2023, there were over 160M workers (source: https://www.bls.gov/charts/employment-situation/civilian-employment.htm), greater than the entire US population when labor force participation was at its lowest — and 22M people higher than two decades ago despite a ~3.5%-4% decline in participation rate.

Are there problems in this country? Absolutely. But we can’t fix them if we ignore basic facts.